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Zhao Z, Yang T, Xiang G, Zhang S, Cai Y, Zhong G, Pu J, Shen C, Zeng J, Chen C, Huang B. A novel small RNA PhaS contributes to polymyxin B-heteroresistance in carbapenem-resistant Klebsiella pneumoniae. Emerg Microbes Infect 2024; 13:2366354. [PMID: 38979571 PMCID: PMC11238654 DOI: 10.1080/22221751.2024.2366354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 06/05/2024] [Indexed: 07/10/2024]
Abstract
In recent years, polymyxin has been used as a last-resort therapy for carbapenem-resistant bacterial infections. The emergence of heteroresistance (HR) to polymyxin hampers the efficacy of polymyxin treatment by amplifying resistant subpopulation. However, the mechanisms behind polymyxin HR remain unclear. Small noncoding RNAs (sRNAs) play an important role in regulating drug resistance. The purpose of this study was to investigate the effects and mechanisms of sRNA on polymyxin B (PB)-HR in carbapenem-resistant Klebsiella pneumoniae. In this study, a novel sRNA PhaS was identified by transcriptome sequencing. PhaS expression was elevated in the PB heteroresistant subpopulation. Overexpression and deletion of PhaS were constructed in three carbapenem-resistant K. pneumoniae strains. Population analysis profiling, growth curve, and time-killing curve analysis showed that PhaS enhanced PB-HR. In addition, we verified that PhaS directly targeted phoP through the green fluorescent protein reporter system. PhaS promoted the expression of phoP, thereby encouraging the expression of downstream genes pmrD and arnT. This upregulation of arnT promoted the 4-amino-4-deoxyL-arabinosaccharide (L-Ara4N) modification of lipid A in PhaS overexpressing strains, thus enhancing PB-HR. Further, within the promoter region of PhaS, specific PhoP recognition sites were identified. ONPG assays and RT-qPCR analysis confirmed that PhaS expression was positively modulated by PhoP and thus up-regulated by PB stimulation. To sum up, a novel sRNA enhancing PB-HR was identified and a positive feedback regulatory pathway of sRNA-PhoP/Q was demonstrated in the study. This helps to provide a more comprehensive and clear understanding of the underlying mechanisms behind polymyxin HR in carbapenem-resistant K. pneumoniae.
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Affiliation(s)
- Zhiwei Zhao
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, People’s Republic of China
| | - Tingting Yang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, People’s Republic of China
| | - Guoxiu Xiang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, People’s Republic of China
| | - Shebin Zhang
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
| | - Yimei Cai
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
| | - Guosheng Zhong
- Department of Clinical Laboratory, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, People’s Republic of China
| | - Jieying Pu
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Guangdong Provincial Key Laboratory of Research on Emergency in TCM, Guangzhou, People’s Republic of China
| | - Cong Shen
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Guangdong Provincial Key Laboratory of Research on Emergency in TCM, Guangzhou, People’s Republic of China
| | - Jianming Zeng
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Guangdong Provincial Key Laboratory of Research on Emergency in TCM, Guangzhou, People’s Republic of China
| | - Cha Chen
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
- Department of Clinical Laboratory, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, People’s Republic of China
| | - Bin Huang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, People’s Republic of China
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Alousi S, Saad J, Panossian B, Makhlouf R, Khoury CA, Rahy K, Thoumi S, Araj GF, Khnayzer R, Tokajian S. Genetic and Structural Basis of Colistin Resistance in Klebsiella pneumoniae: Unraveling the Molecular Mechanisms. J Glob Antimicrob Resist 2024:S2213-7165(24)00128-0. [PMID: 39029657 DOI: 10.1016/j.jgar.2024.06.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 05/28/2024] [Accepted: 06/23/2024] [Indexed: 07/21/2024] Open
Abstract
BACKGROUND Antimicrobial Antimicrobial resistance (AMR), together with multi-drug resistant (MDR), mainly among Gram-negative bacteria, has been on the rise. Colistin (polymyxin E) remains one of the primary available last resorts to treat infections by MDR bacteria with the rapid emergence of global resistance. OBJECTIVES Since the exact mechanism of bacterial resistance to colistin remains unfolded, this study warranted elucidating the underlying mechanism of colistin resistance and heteroresistance among carbapenem-resistant (CR) Klebsiella pneumoniae isolates. METHODS Molecular analysis was carried out on the resistant isolates using a genome-wide characterization approach, and MALDI-TOF MS for lipid A. RESULTS Among the 32 CR K. pneumoniae isolates, several isolates showed resistance and intermediate resistance, to colistin. The seven isolates with intermediate resistance exhibited the "skip-well" phenomenon, attributed to the presence of resistant subpopulations. The three isolates with full resistance to colistin showed ions using MALDI-TOF MS at m/z 1840 and 1824 representing bisphosphorylated and hexaacylated lipid A with or without hydroxylation, at position C'-2 of the fatty acyl chain, respectively. Studying the genetic environment of mgrB locus revealed the presence of insertion sequences that disrupted the mgrB locus in the three colistin resistant isolates: IS1R and IS903B. CONCLUSIONS Our findings showed that colistin resistance/heteroresistance was inducible with mutations in chromosomal regulatory networks controlling lipid A moiety and IS sequences disrupting the mgrB gene, leading to elevated MIC values and treatment failure. Different treatment strategies should be employed to avoid colistin heteroresistance-linked treatment failures, mainly through combination therapy using colistin with carbapenems, aminoglycosides, or tigecycline.
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Affiliation(s)
- Sahar Alousi
- Lebanese American University, Department of Natural Sciences, Byblos, Lebanon
| | - Jamal Saad
- Lebanese University, Department of Sciences, Beirut, Lebanon
| | - Balig Panossian
- Lebanese American University, Department of Natural Sciences, Byblos, Lebanon
| | - Rita Makhlouf
- Lebanese American University, Department of Natural Sciences, Byblos, Lebanon
| | - Charbel Al Khoury
- Lebanese American University, Department of Natural Sciences, Byblos, Lebanon
| | - Kelven Rahy
- Lebanese American University, School of Medicine, Byblos, Lebanon
| | - Sergio Thoumi
- Lebanese American University, Department of Computer Science and Mathematics, Beirut, Lebanon
| | - George F Araj
- Department of Pathology and Laboratory Medicine, Faculty of Medicine, American University of Beirut Medical Center, Beirut, Lebanon
| | - Rony Khnayzer
- Lebanese American University, Department of Natural Sciences, Byblos, Lebanon
| | - Sima Tokajian
- Lebanese American University, Department of Natural Sciences, Byblos, Lebanon.
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Sánchez-León I, Pérez-Nadales E, Marín-Sanz JA, García-Martínez T, Martínez-Martínez L. Heteroresistance to colistin in wild-type Klebsiella pneumoniae isolates from clinical origin. Microbiol Spectr 2023; 11:e0223823. [PMID: 37962370 PMCID: PMC10714954 DOI: 10.1128/spectrum.02238-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 10/13/2023] [Indexed: 11/15/2023] Open
Abstract
IMPORTANCE Colistin is one of the last remaining therapeutic options for dealing with Enterobacteriaceae. Unfortunately, heteroresistance to colistin is also rapidly increasing. We described the prevalence of colistin heteroresistance in a variety of wild-type strains of Klebsiella pneumoniae and the evolution of these strains with colistin heteroresistance to a resistant phenotype after colistin exposure and withdrawal. Resistant mutants were characterized at the molecular level, and numerous mutations in genes related to lipopolysaccharide formation were observed. In colistin-treated patients, the evolution of K. pneumoniae heteroresistance to resistance phenotype could lead to higher rates of therapeutic failure.
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Affiliation(s)
- Irene Sánchez-León
- Maimonides Biomedical Research Institute of Cordoba, Cordoba, Spain
- Department of Agricultural Chemistry, Edaphology and Microbiology, University of Cordoba, Cordoba, Spain
| | - Elena Pérez-Nadales
- Maimonides Biomedical Research Institute of Cordoba, Cordoba, Spain
- Department of Agricultural Chemistry, Edaphology and Microbiology, University of Cordoba, Cordoba, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Juan Antonio Marín-Sanz
- Maimonides Biomedical Research Institute of Cordoba, Cordoba, Spain
- Department of Computer Sciences, University of Cordoba, Cordoba, Spain
| | - Teresa García-Martínez
- Department of Agricultural Chemistry, Edaphology and Microbiology, University of Cordoba, Cordoba, Spain
| | - Luis Martínez-Martínez
- Maimonides Biomedical Research Institute of Cordoba, Cordoba, Spain
- Department of Agricultural Chemistry, Edaphology and Microbiology, University of Cordoba, Cordoba, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
- Clinical Unit of Microbiology, Reina Sofía University Hospital, Cordoba, Spain
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Rajakani SG, Xavier BB, Sey A, Mariem EB, Lammens C, Goossens H, Glupczynski Y, Malhotra-Kumar S. Insight into Antibiotic Synergy Combinations for Eliminating Colistin Heteroresistant Klebsiella pneumoniae. Genes (Basel) 2023; 14:1426. [PMID: 37510330 PMCID: PMC10378790 DOI: 10.3390/genes14071426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 07/30/2023] Open
Abstract
Colistin heteroresistance has been identified in several bacterial species, including Escherichia coli and Klebsiella pneumoniae, and may underlie antibiotic therapy failures since it most often goes undetected by conventional antimicrobial susceptibility tests. This study utilizes population analysis profiling (PAP) and time-kill assay for the detection of heteroresistance in K. pneumoniae and for evaluating the association between in vitro regrowth and heteroresistance. The mechanisms of colistin resistance and the ability of combination therapies to suppress resistance selection were also analysed. In total, 3 (18%) of the 16 colistin-susceptible strains (MIC ≤ 2 mg/L) were confirmed to be heteroresistant to colistin by PAP assay. In contrast to the colistin-susceptible control strains, all three heteroresistant strains showed regrowth when exposed to colistin after 24 h following a rapid bactericidal action. Colistin resistance in all the resistant subpopulations was due to the disruption of the mgrB gene by various insertion elements such as ISKpn14 of the IS1 family and IS903B of the IS5 family. Colistin combined with carbapenems (imipenem, meropenem), aminoglycosides (amikacin, gentamicin) or tigecycline was found to elicit in vitro synergistic effects against these colistin heteroresistant strains. Our experimental results showcase the potential of combination therapies for treatment of K. pneumoniae infections associated with colistin heteroresistance.
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Affiliation(s)
- Sahaya Glingston Rajakani
- Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, 2610 Antwerp, Belgium
| | - Basil Britto Xavier
- Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, 2610 Antwerp, Belgium
| | - Adwoa Sey
- Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, 2610 Antwerp, Belgium
| | - El Bounja Mariem
- Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, 2610 Antwerp, Belgium
| | - Christine Lammens
- Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, 2610 Antwerp, Belgium
| | - Herman Goossens
- Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, 2610 Antwerp, Belgium
| | - Youri Glupczynski
- Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, 2610 Antwerp, Belgium
| | - Surbhi Malhotra-Kumar
- Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, 2610 Antwerp, Belgium
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Zahedi Bialvaei A, Eslami P, Ganji L, Dolatyar Dehkharghani A, Asgari F, Koupahi H, Barzegarian Pashacolaei HR, Rahbar M. Prevalence and epidemiological investigation of mgrB-dependent colistin resistance in extensively drug resistant Klebsiella pneumoniae in Iran. Sci Rep 2023; 13:10680. [PMID: 37393362 PMCID: PMC10314893 DOI: 10.1038/s41598-023-37845-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 06/28/2023] [Indexed: 07/03/2023] Open
Abstract
Carbapenemases-producing K. pneumoniae are challenging antimicrobial therapy of hospitalised patients, which is further complicated by colistin resistance. The aim of this study was to investigate the molecular epidemiological insights into carbapenemases-producing and colistin-resistant clinical K. pneumoniaeA total of 162 colistin resistant clinical strains of K. pneumoniae were collected during 2017-2019. Antimicrobial susceptibility and the colistin minimum inhibitory concentration were determined. Using PCR assay, the prevalence of resistance-associated genes including blaKPC, blaIMP, blaVIM, blaOXA-48, blaNDM-1 and mcr-1 to -9 was examined. Additionally, a PCR assay was used to examine the mgrB gene in colistin-resistant bacteria. 94.4% of the tested strains were resistant to imipenem and 96.3% were resistant to meropenem. Colistin resistance (MIC > 4 µg/L) was observed in 161 isolates (99.4%) by Colistin Broth Disk Elution method. The KPC enzyme was the most common carbapenemase and was identified in 95 strains (58.6%), followed by the IMP, VIM and OXA-48 detected in 47 (29%), 23 (14.2%) and 12 (7.4%) isolates, respectively. However, no NDM-1 gene was detected. Additionally, none of the studied isolates harbored mcr variants, while mgrB gene was observed in 152 (92.6%) isolates. Colistin resistance of K. pneumoniae isolates may be associated with mgrB gene mutation. To stop the spread of resistant K. pneumoniae, surveillance must be improved, infection prevention protocols must be followed, and antibiotic stewardship must be practised.
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Affiliation(s)
- Abed Zahedi Bialvaei
- Microbial Biotechnology Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Parisa Eslami
- Department of Microbiology, Milad Hospital, Tehran, Iran
| | - Leila Ganji
- Department of Microbiology, Ministry of Health & Medical Education, Iranian Reference Health Laboratories Research Center, Tehran, Iran
| | - Alireza Dolatyar Dehkharghani
- Department of Microbiology, Ministry of Health & Medical Education, Iranian Reference Health Laboratories Research Center, Tehran, Iran
| | - Farhad Asgari
- Department of Microbiology, Ministry of Health & Medical Education, Iranian Reference Health Laboratories Research Center, Tehran, Iran
| | - Hossein Koupahi
- Department of Microbiology, Islamic Azad University, Varamin-Pishva Branch, Varamin, Iran
| | | | - Mohammad Rahbar
- Department of Microbiology, Ministry of Health & Medical Education, Iranian Reference Health Laboratories Research Center, Tehran, Iran.
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Sánchez-León I, García-Martínez T, Diene SM, Pérez-Nadales E, Martínez-Martínez L, Rolain JM. Heteroresistance to Colistin in Clinical Isolates of Klebsiella pneumoniae Producing OXA-48. Antibiotics (Basel) 2023; 12:1111. [PMID: 37508209 PMCID: PMC10375995 DOI: 10.3390/antibiotics12071111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 06/21/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023] Open
Abstract
Heteroresistance to colistin can be defined as the presence of resistant subpopulations in an isolate that is susceptible to this antibiotic. Colistin resistance in Gram-negative bacteria is more frequently related to chromosomal mutations and insertions. This work aimed to study heteroresistance in nine clinical isolates of Klebsiella pneumoniae producing OXA-48 and to describe genomic changes in mutants with acquired resistance in vitro. Antimicrobial susceptibility was determined by broth microdilution (BMD) and heteroresistance by population analysis profiling (PAP). The proteins related to colistin resistance were analyzed for the presence of mutations. Additionally, PCR of the mgrB gene was performed to identify the presence of insertions. In the nine parental isolates, the PAP method showed colistin heteroresistance of colonies growing on plates with concentrations of up to 64 mg/L, corresponding to stable mutant subpopulations. The MICs of some mutants from the PAP plate containing 4×MIC of colistin had absolute values of ≤2 mg/L that were higher than the parental MICs and were defined as persistent variants. PCR of the mgrB gene identified an insertion sequence that inactivated the gene in 21 mutants. Other substitutions in the investigated mutants were found in PhoP, PhoQ, PmrB, PmrC, CrrA and CrrB proteins. Colistin heteroresistance in K. pneumoniae isolates was attributed mainly to insertions in the mgrB gene and point mutations in colistin resistance proteins. The results of this study will improve understanding regarding the mechanisms of colistin resistance in mutants of K. pneumoniae producing OXA-48.
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Affiliation(s)
- Irene Sánchez-León
- Maimonides Biomedical Research Institute of Cordoba, 14004 Cordoba, Spain
- Department of Agricultural Chemistry, Edaphology and Microbiology, Agrifood Campus of International Excellence CeiA3, University of Cordoba, 14014 Cordoba, Spain
| | - Teresa García-Martínez
- Department of Agricultural Chemistry, Edaphology and Microbiology, Agrifood Campus of International Excellence CeiA3, University of Cordoba, 14014 Cordoba, Spain
| | - Seydina M Diene
- Microbes Evolution Phylogeny and Infections (MEPHI), IRD, APHM, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-University, 13005 Marseille, France
| | - Elena Pérez-Nadales
- Maimonides Biomedical Research Institute of Cordoba, 14004 Cordoba, Spain
- Department of Agricultural Chemistry, Edaphology and Microbiology, Agrifood Campus of International Excellence CeiA3, University of Cordoba, 14014 Cordoba, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Luis Martínez-Martínez
- Maimonides Biomedical Research Institute of Cordoba, 14004 Cordoba, Spain
- Department of Agricultural Chemistry, Edaphology and Microbiology, Agrifood Campus of International Excellence CeiA3, University of Cordoba, 14014 Cordoba, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Clinical Unit of Microbiology, Reina Sofía University Hospital, 14004 Cordoba, Spain
| | - Jean-Marc Rolain
- Microbes Evolution Phylogeny and Infections (MEPHI), IRD, APHM, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-University, 13005 Marseille, France
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Jo J, Kwon KT, Ko KS. Multiple heteroresistance to tigecycline and colistin in Acinetobacter baumannii isolates and its implications for combined antibiotic treatment. J Biomed Sci 2023; 30:37. [PMID: 37287044 DOI: 10.1186/s12929-023-00914-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 03/21/2023] [Indexed: 06/09/2023] Open
Abstract
BACKGROUND We investigated the presence of heteroresistance against both tigecycline and colistin in Acinetobacter baumannii and then evaluated the effectiveness of combined antibiotic treatment given the existence of discrete tigecycline- and colistin-resistant subpopulations. METHODS We performed population analysis profiling (PAP) to evaluate the degree of composite heteroresistance in A. baumannii isolates, with the extent of this resistance quantified using subsequent antibiotic susceptibility testing. We then evaluated the amino acid sequence of PmrBAC and the relative mRNA expression levels of pmrB. Finally, we investigated the combined antibiotic efficacy of tigecycline and colistin in multiple-heteroresistant isolates using dual PAP and in vitro time-killing assays. RESULTS All tigecycline-heteroresistant A. baumannii isolates, with the exception of one colistin-resistant isolate, were also heteroresistant to colistin. Evaluations of the colistin-resistant subpopulations revealed amino acid alterations in PmrA and PmrB and increased expression of pmrB. All tigecycline-resistant subpopulations were susceptible to colistin, and all colistin-resistant subpopulations were susceptible to tigecycline. Dual PAP analysis using tigecycline and colistin showed no heteroresistance, and in vitro time-killing assays revealed that a combination of these two antibiotics effectively eliminated the bacterial cells. CONCLUSION Our results suggest that multiple heteroresistance to tigecycline and colistin is highly prevalent among A. baumannii clinical isolates and that these resistant subpopulations exist independently in single multiple heteroresistant isolates. Therefore, our findings may explain the success of combined antibiotic therapies in these infections.
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Affiliation(s)
- Jeongwoo Jo
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea
| | - Ki Tae Kwon
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Kwan Soo Ko
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea.
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Roch M, Sierra R, Andrey DO. Antibiotic heteroresistance in ESKAPE pathogens, from bench to bedside. Clin Microbiol Infect 2023; 29:320-325. [PMID: 36270588 DOI: 10.1016/j.cmi.2022.10.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 09/23/2022] [Accepted: 10/13/2022] [Indexed: 11/27/2022]
Abstract
BACKGROUND Heteroresistance refers to subpopulation-mediated differential antimicrobial susceptibility within a clonal bacterial population. Usually, it designates a resistant subpopulation identified within an isolate considered susceptible by classical antimicrobial susceptibility testing. Heteroresistance lacks a uniform microbiological definition for diagnostic laboratories, and its clinical impact remains unclear for most bacterial species. OBJECTIVES This narrative review aims to provide a practical overview on the latest developments in the field of heteroresistance for both clinical microbiologists and physicians, with a particular focus on ESKAPE pathogens. SOURCES A literature search was performed on Pubmed and Google with the key words heteroresistance (heterogeneity OR heterogeneous) AND antibiotic resistance. Among the 836 publications selected based on their abstracts, the most relevant for the detection, epidemiology and clinical impact of heteroresistance in ESKAPE pathogens are discussed here. CONTENT Heteroresistance is only clearly defined for heterogeneous vancomycin intermediate Staphylococcus aureus. We compiled a larger microbiological definition to be applicable to other bacterial species and antibiotics in the clinical context. We highlighted the key technical points of population analysis profile, which is the reference standard for detecting heteroresistance. Heteroresistance to polymyxins, β-lactams (carbapenems, cefiderocol), fosfomycin, tigecycline and aminoglycosides is frequently reported in multidrug-resistant gram-negative pathogens. Treatment failure due to heteroresistance has been described in case reports or retrospective studies, so far confirmed by meta-analyses in the case of heterogeneous vancomycin intermediate S. aureus only. Finally, to treat pandrug-resistant bacterial infections, the option of targeting susceptible subpopulations of resistant isolates using tailored antibiotic combinations is also discussed. IMPLICATIONS Systematic heteroresistance screening by clinical laboratories is not currently recommended. Nevertheless, we should be aware of this phenomenon, and in specific cases, such as treatment failure, heteroresistance should be tested by reference laboratories. Additional studies using standardized methods are needed to improve our understanding of heteroresistance and further assess its clinical impact.
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Affiliation(s)
- Mélanie Roch
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Roberto Sierra
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland; Division of Infectious Diseases, Department of Medicine, Geneva University Hospitals and Medical School, Geneva, Switzerland
| | - Diego O Andrey
- Division of Infectious Diseases, Department of Medicine, Geneva University Hospitals and Medical School, Geneva, Switzerland; Division of Laboratory Medicine, Department of Diagnostics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
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Zha L, Zhang X, Cheng Y, Xu Q, Liu L, Chen S, Lu Z, Guo J, Tefsen B. Intravenous Polymyxin B as Adjunctive Therapy to High-Dose Tigecycline for the Treatment of Nosocomial Pneumonia Due to Carbapenem-Resistant Acinetobacter baumannii and Klebsiella pneumoniae: A Propensity Score-Matched Cohort Study. Antibiotics (Basel) 2023; 12:antibiotics12020273. [PMID: 36830183 PMCID: PMC9952519 DOI: 10.3390/antibiotics12020273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/13/2023] [Accepted: 01/17/2023] [Indexed: 02/03/2023] Open
Abstract
Although the combination of polymyxin and tigecycline is widely used in treating carbapenem-resistant bacterial infections, the benefit of this combination is still uncertain. To assess whether adding polymyxin B to the high-dose tigecycline regimen would result in better clinical outcomes than the high-dose tigecycline therapy in patients with pneumonia caused by carbapenem-resistant Klebsiella pneumoniae and Acinetobacter baumannii, we conducted a propensity score-matched cohort study in a single center between July 2019 and December 2021. Of the 162 eligible patients, 102 were included in the 1:1 matched cohort. The overall 14-day mortality in the matched cohort was 24.5%. Compared with high-dose tigecycline, the combination therapy was not associated with better clinical outcomes, and showed similar 14-day mortality (OR, 0.72, 95% CI 0.27-1.83, p = 0.486), clinical cure (OR, 1.09, 95% CI 0.48-2.54, p = 0.823), microbiological cure (OR, 0.96, 95% CI 0.39-2.53, p = 0.928) and rate of nephrotoxicity (OR 0.85, 95% CI 0.36-1.99, p = 0.712). Subgroup analyses also did not demonstrate any statistical differences. Based on these results, it is reasonable to recommend against adding polymyxin B to the high-dose tigecycline regimen in treating pneumonia caused by carbapenem-resistant K. pneumoniae and A. baumannii.
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Affiliation(s)
- Lei Zha
- Department of Respiratory Medicine, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital of Wannan Medical College), Wuhu 241000, China
- Institute of Infection and Global Health, University of Liverpool, Liverpool L69 7BE, UK
| | - Xue Zhang
- Department of Intensive Care Unit, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Yusheng Cheng
- Department of Respiratory Medicine, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital of Wannan Medical College), Wuhu 241000, China
| | - Qiancheng Xu
- Department of Critical Care Medicine, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital of Wannan Medical College), Wuhu 241000, China
| | - Lingxi Liu
- Department of Intensive Care Unit, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Simin Chen
- Department of Intensive Care Unit, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Zhiwei Lu
- Department of Respiratory Medicine, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital of Wannan Medical College), Wuhu 241000, China
| | - Jun Guo
- Department of Intensive Care Unit, West China Hospital, Sichuan University, Chengdu 610041, China
- Correspondence: (J.G.); (B.T.)
| | - Boris Tefsen
- Division of Microbiology, Department of Biology, Utrecht University, 3584 CH Utrecht, The Netherlands
- Natural Sciences, Ronin Institute, Montclair, NJ 07043, USA
- Correspondence: (J.G.); (B.T.)
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10
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Chiu S, Hancock AM, Schofner BW, Sniezek KJ, Soto-Echevarria N, Leon G, Sivaloganathan DM, Wan X, Brynildsen MP. Causes of polymyxin treatment failure and new derivatives to fill the gap. J Antibiot (Tokyo) 2022; 75:593-609. [PMID: 36123537 DOI: 10.1038/s41429-022-00561-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 08/29/2022] [Accepted: 08/30/2022] [Indexed: 11/08/2022]
Abstract
Polymyxins are a class of antibiotics that were discovered in 1947 from programs searching for compounds effective in the treatment of Gram-negative infections. Produced by the Gram-positive bacterium Paenibacillus polymyxa and composed of a cyclic peptide chain with a peptide-fatty acyl tail, polymyxins exert bactericidal effects through membrane disruption. Currently, polymyxin B and colistin (polymyxin E) have been developed for clinical use, where they are reserved as "last-line" therapies for multidrug-resistant (MDR) infections. Unfortunately, the incidences of strains resistant to polymyxins have been increasing globally, and polymyxin heteroresistance has been gaining appreciation as an important clinical challenge. These phenomena, along with bacterial tolerance to this antibiotic class, constitute important contributors to polymyxin treatment failure. Here, we review polymyxins and their mechanism of action, summarize the current understanding of how polymyxin treatment fails, and discuss how the next generation of polymyxins holds promise to invigorate this antibiotic class.
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Affiliation(s)
- Selena Chiu
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Anna M Hancock
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Bob W Schofner
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Katherine J Sniezek
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | | | - Gabrielle Leon
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | | | - Xuanqing Wan
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Mark P Brynildsen
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA.
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
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11
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Characterization of Carbapenemase-Producing Klebsiella pneumoniae Isolates from Two Romanian Hospitals Co-Presenting Resistance and Heteroresistance to Colistin. Antibiotics (Basel) 2022; 11:antibiotics11091171. [PMID: 36139950 PMCID: PMC9495256 DOI: 10.3390/antibiotics11091171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 08/12/2022] [Accepted: 08/29/2022] [Indexed: 11/16/2022] Open
Abstract
Klebsiella pneumoniae is a notorious human pathogen involved in healthcare-associated infections. The worldwide expansion of infections induced by colistin-resistant and carbapenemase-producing Enterobacterales (CPE) isolates has been increasingly reported. This study aims to analyze the phenotypic and molecular profiles of 10 colistin-resistant (CR) isolates and 2 pairs of colistin-heteroresistant (ChR) (parental and the corresponding resistant mutants) isolates of K. pneumoniae CPE sourced from two hospitals. The phenotypes of strains in the selected collection had been previously characterized. Antimicrobial susceptibility testing was performed using a Vitek 2 Compact system (BioMérieux SA, Marcy l’Etoile, France), the disc diffusion method, and broth microdilution (BMD) for colistin. Whole-genome sequencing (WGS) did not uncover evidence of any mobile colistin resistance (mcr) genes, although the mgrB gene of seven isolates appeared to be disrupted by insertion sequences (ISKpn25 or ISKpn26). Possible deleterious missense mutations were found in phoP (L4F), phoQ (Q426L, L26Q, L224Q, Q317K), pmrB (R256G, P95L, T157P, V352E), and crrB (P151S) genes. The identified isolates belonged to the following clonal lineages: ST101 (n = 6), ST147 (n = 5), ST258 (n = 2), and ST307 (n = 1). All strains harbored IncF plasmids. OXA-48 producers carried IncL and IncR plasmids, while one blaNDM-1 genome was found to harbor IncC plasmids. Ceftazidime–avibactam remains a therapeutic option for KPC-2 and OXA-48 producers. Resistance to meropenem–vaborbactam has emerged in some blakPC-2-carrying isolates. Our study demonstrates that the results of WGS can provide essential evidence for the surveillance of antimicrobial resistance.
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12
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Panigrahi K, Pathi BK, Poddar N, Sabat S, Pradhan S, Pattnaik D, Patro S, Praharaj AK. Colistin Resistance Among Multi-Drug Resistant Gram-Negative Bacterial Isolates From Different Clinical Samples of ICU Patients: Prevalence and Clinical Outcomes. Cureus 2022; 14:e28317. [PMID: 36158344 PMCID: PMC9499824 DOI: 10.7759/cureus.28317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/23/2022] [Indexed: 11/26/2022] Open
Abstract
Introduction: Colistin is considered to be the last resort for the management of infections caused by multi-drug resistant (MDR) gram-negative bacilli (GNB). However, in the recent past, there has been a rise in colistin resistance among MDR isolates in clinical settings with no profound data on the incidences and causes. The purpose of this study was to estimate the prevalence of colistin-resistance (CLR) in MDR isolates collected from different intensive care units (ICUs) and to determine the clinical outcomes of the patients. Materials and methods: A prospective study was conducted in the ICU of a tertiary care hospital in Eastern Odisha, India from March 2019 to February 2020. MDR GNB isolates from different clinical samples of ICU patients, not intrinsically resistant to colistin, were included in this study. Samples collected for culture and sensitivity testing were processed as per standard guidelines in the microbiology laboratory. MDR organisms were examined for colistin susceptibility by the broth dilution method. Clinical data was collected from hospital electronic medical records and presented as percentage, number (N), and median (range). Results: The prevalence of colistin resistance MDR GNB was found to be 19.6% in the present study. Colistin resistance among the MDR isolates was found to be the highest (9.2% for Klebsiella pneumonia followed by 5% for Escherichia coli). CLR drug-resistant isolates were commonly (28.8%) isolated from samples of respiratory tract infections and the majority (54.1%) were from neurology ICU. In this study, co-morbidity was not found among 57.9% of the ICU patients and recovery was maximum i.e., 74.2%. Conclusion: This study found the prevalence of colistin resistance to be high (19.6%) among all MDR GNB isolates from samples of ICU patients, Klebsiella pneumonia and Escherichia coli commonly acquire colistin resistance. Patients in the neurology ICU were frequently infected with CLR MDR strains. Most of the patients who recovered were without any underlying comorbidities. Prolonged hospital stay and direct antibiotic pressure in the hospital can lead to the development of CLR variants.
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13
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Kapel N, Caballero JD, MacLean RC. Localized pmrB hypermutation drives the evolution of colistin heteroresistance. Cell Rep 2022; 39:110929. [PMID: 35675785 PMCID: PMC9189680 DOI: 10.1016/j.celrep.2022.110929] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 12/02/2021] [Accepted: 05/16/2022] [Indexed: 11/16/2022] Open
Abstract
Colistin has emerged as an important last line of defense for the treatment of infections caused by antibiotic-resistant gram-negative pathogens, but colistin resistance remains poorly understood. Here, we investigate the responses of ≈1,000 populations of a multi-drug-resistant (MDR) strain of P. aeruginosa to a high dose of colistin. Colistin exposure causes rapid cell death, but some populations eventually recover due to the growth of sub-populations of heteroresistant cells. Heteroresistance is unstable, and resistance is rapidly lost under culture in colistin-free medium. The evolution of heteroresistance is primarily driven by selection for heteroresistance at two hotspot sites in the PmrAB regulatory system. Localized hypermutation of pmrB generates colistin resistance at 103–104 times the background resistance mutation rate (≈2 × 10-5 per cell division). PmrAB provides resistance to antimicrobial peptides that are involved in host immunity, suggesting that this pathogen may have evolved a highly mutable pmrB as an adaptation to host immunity. Pseudomonas populations recover from colistin due to the growth of heteroresistant cells Heteroresistance is driven by pre-existing mutations in the PmrAB regulatory system pmrB mutations arise at 103–104 times the background mutation rate Heteroresistance is unstable and is rapidly lost in the absence of colistin
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Affiliation(s)
- Natalia Kapel
- University of Oxford, Department of Zoology, 11a Mansfield Road, Oxford OX1 3SZ, UK
| | - Julio Diaz Caballero
- University of Oxford, Department of Zoology, 11a Mansfield Road, Oxford OX1 3SZ, UK
| | - R Craig MacLean
- University of Oxford, Department of Zoology, 11a Mansfield Road, Oxford OX1 3SZ, UK.
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14
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Főldes A, Székely E, Voidăzan ST, Dobreanu M. Comparison of Six Phenotypic Assays with Reference Methods for Assessing Colistin Resistance in Clinical Isolates of Carbapenemase-Producing Enterobacterales: Challenges and Opportunities. Antibiotics (Basel) 2022; 11:antibiotics11030377. [PMID: 35326840 PMCID: PMC8944616 DOI: 10.3390/antibiotics11030377] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 02/27/2022] [Accepted: 03/09/2022] [Indexed: 02/01/2023] Open
Abstract
The global escalation of severe infections due to carbapenemase-producing Enterobacterales (CPE) isolates has prompted increased usage of parenteral colistin. Considering the reported difficulties in assessing their susceptibility to colistin, the purpose of the study was to perform a comparative evaluation of six phenotypic assays—the colistin broth disc elution (CBDE), Vitek 2 Compact (bioMérieux SA, Marcy l’Etoile, France), the Micronaut MIC-Strip Colistin (Merlin Diagnostika GMBH, Bornheim-Hensel, Germany), the gradient diffusion strip Etest (bioMérieux SA, Marcy l’Etoile, France), ChromID Colistin R Agar (COLR) (bioMérieux SA, Marcy l’Etoile, France), and the Rapid Polymyxin NP Test (ELITechGroup, Signes, France)—versus the reference method of broth microdilution (BMD). All false resistance results were further assessed using population analysis profiling (PAP). Ninety-two nonrepetitive clinical CPE strains collected from two hospitals were evaluated. The BMD confirmed 36 (39.13%) isolates susceptible to colistin. According to the BMD, the Micronaut MIC-Strip Colistin, the CBDE, and the COLR medium exhibited category agreement (CA) of 100%. In comparison with the BMD, the highest very major discrepancy (VMD) was noted for Etest (n = 15), and the only false resistance results were recorded for the Rapid Polymyxin NP Test (n = 3). Only the PAP method and the Rapid Polymyxin NP Test were able to detect heteroresistant isolates (n = 2). Thus, there is an urgent need to further optimize the diagnosis strategies for colistin resistance.
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Affiliation(s)
- Annamária Főldes
- Department of Microbiology, Laboratory of Medical Analysis, “Dr. Constantin Opriş” County Emergency Hospital, 430031 Baia Mare, Romania
- Doctoral School of Medicine and Pharmacy, “George Emil Palade” University of Medicine, Pharmacy, Science and Technology, 540142 Targu Mures, Romania
- Correspondence:
| | - Edit Székely
- Department of Microbiology, Central Clinical Laboratory, County Emergency Clinical Hospital, 540136 Targu Mures, Romania;
- Department of Microbiology, “George Emil Palade” University of Medicine, Pharmacy, Science and Technology, 540142 Targu Mures, Romania
| | - Septimiu Toader Voidăzan
- Department of Epidemiology, “George Emil Palade’’ University of Medicine, Pharmacy, Science and Technology, 540142 Targu Mures, Romania;
| | - Minodora Dobreanu
- Department of Clinical Biochemistry, Central Clinical Laboratory, County Emergency Clinical Hospital, 540136 Targu Mures, Romania;
- Department of Laboratory Medicine, “George Emil Palade” University of Medicine, Pharmacy, Science and Technology, 540142 Targu Mures, Romania
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15
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Li J, Tang M, Xia F, Min C, Hu Y, Wang H, Zou M. Emergence of polymyxin B-heteroresistant hypervirulent Klebsiella pneumoniae from an individual in the community with asymptomatic bacteriuria. BMC Microbiol 2022; 22:47. [PMID: 35130831 PMCID: PMC8818840 DOI: 10.1186/s12866-022-02462-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 01/31/2022] [Indexed: 01/11/2023] Open
Abstract
Background The heteroresistance of polymyxin B, a last-resort antibiotic used to treat many serious bacterial infections, may lead to antibiotic treatment failure. However, polymyxin B-heteroresistant isolates are rare in individuals living in the community. We report a polymyxin B-heteroresistant hypervirulent Klebsiella pneumoniae (hvKP) isolate from an individual in the community with asymptomatic bacteriuria. Results The NYTJ35 isolate had multiple virulence genes that encoded a mucoid phenotype regulator (rmpA), aerobactin (iucABCD-iutA), salmochelin (iroBCDN), yersiniabactin (irp1–2 and ybtAEPQSTUX), and a truncated rmpA2. Infection of galleria mellonella larvae indicated the isolate was hypervirulent. Antimicrobial susceptibility testing showed it was susceptible to all tested antibiotics except polymyxin B. The proportion of surviving bacteria was 1.2 × 10− 7 based on the population analysis profile (PAP) method, suggesting the presence of polymyxin B heteroresistance. The isolate was not hypermucoviscous, but it was a strong biofilm producer. It had capsular serotype K1 and belonged to sequence type 23 (ST23). The isolate also had the D150G substitution in phoQ, which is known to confer polymyxin B resistance. Conclusions We identified the co-occurrence of hypervirulence and polymyxin B heteroresistance in a K. pneumoniae isolate from an individual with asymptomatic bacteriuria. We suggest the use of increased screening for hvKP in individuals living in the community.
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Affiliation(s)
- Jun Li
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Mengli Tang
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Fengjun Xia
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Changhang Min
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Yongmei Hu
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Haichen Wang
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Mingxiang Zou
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China. .,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
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16
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Stojowska-Swędrzyńska K, Łupkowska A, Kuczyńska-Wiśnik D, Laskowska E. Antibiotic Heteroresistance in Klebsiella pneumoniae. Int J Mol Sci 2021; 23:449. [PMID: 35008891 PMCID: PMC8745652 DOI: 10.3390/ijms23010449] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 12/28/2021] [Accepted: 12/29/2021] [Indexed: 12/12/2022] Open
Abstract
Klebsiella pneumoniae is one of the most common pathogens responsible for infections, including pneumonia, urinary tract infections, and bacteremias. The increasing prevalence of multidrug-resistant K. pneumoniae was recognized in 2017 by the World Health Organization as a critical public health threat. Heteroresistance, defined as the presence of a subpopulation of cells with a higher MIC than the dominant population, is a frequent phenotype in many pathogens. Numerous reports on heteroresistant K. pneumoniae isolates have been published in the last few years. Heteroresistance is difficult to detect and study due to its phenotypic and genetic instability. Recent findings provide strong evidence that heteroresistance may be associated with an increased risk of recurrent infections and antibiotic treatment failure. This review focuses on antibiotic heteroresistance mechanisms in K. pneumoniae and potential therapeutic strategies against antibiotic heteroresistant isolates.
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Affiliation(s)
| | | | | | - Ewa Laskowska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (K.S.-S.); (A.Ł.); (D.K.-W.)
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17
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Combined effect of Polymyxin B and Tigecycline to overcome Heteroresistance in Carbapenem-Resistant Klebsiella pneumoniae. Microbiol Spectr 2021; 9:e0015221. [PMID: 34704782 PMCID: PMC8549724 DOI: 10.1128/spectrum.00152-21] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We assessed the prevalence of polymyxin B (PMB)- and tigecycline (TGC)-heteroresistant Klebsiella pneumoniae isolates and investigated the combined effect of PMB and TGC against dual-heteroresistant K. pneumoniae. Ninety-five nonduplicated carbapenem-resistant K. pneumoniae (CRKP) clinical isolates were collected from a tertiary-care teaching hospital in China. PCR was used to detect the resistant genes among the CRKP isolates. Population analysis profiling (PAP) was carried out to evaluate the existence of heteroresistance. A time-kill assay of PMB combined with TGC was conducted against heteroresistant K. pneumoniae strains. Real-time PCR was performed to determine the pmrA, phoP, and acrB expression levels. Among them, 74 isolates (77.9%) were susceptible to TGC, and 90 isolates (94.7%) were susceptible to PMB. In addition, of the TGC-susceptible isolates, 49 strains (66.2%) exhibited heteroresistant phenotypes. All of the PMB-susceptible isolates showed heteroresistant phenotypes. Forty-six isolates (48.4%) were heteroresistant to both TGC and PMB. All of the isolates carried the blaKPC gene, and one strain carried both blaKPC and blaNDM genes. The time-kill assay revealed in four isolates that early bactericidal activity could be triggered by the combination of PMB and TGC, and there was no regrowth, even at a relatively lower concentration (0.125 mg/liter PMB with 1 mg/liter TGC). Upregulated expression of pmrA, phoP, and acrB indicated that heteroresistance could be related to two-component systems and the AcrAB-TolC efflux pump. The combination of PMB and TGC may be a treatment strategy for those infected with CRKP heteroresistant to PMB and/or TGC. IMPORTANCE Tigecycline and colistin are two of the last treatment options remaining for carbapenem-resistant Enterobacteriaceae. Unfortunately, tigecycline resistance and colistin heteroresistance are also increasing rapidly. In the current study, we identified a high prevalence of heteroresistance to both PMB and TGC among clinical isolates of carbapenem-resistant K. pneumoniae (CRKP). The resistant subpopulations could survive pressure from TGC or PMB but were killed by the combination at a relatively low dose. It is proposed that the combination of PMB and TGC may be a treatment strategy for patients who are infected with CRKP heteroresistant to PMB or TGC.
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18
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Wang Y, Berglund B, Zhu Y, Luo Q, Xiao Y. Performance of different methods for testing polymyxin B: comparison of broth microdilution, agar dilution and MIC test strip in mcr-1 positive and negative Escherichia coli. Lett Appl Microbiol 2021; 73:197-205. [PMID: 33904164 DOI: 10.1111/lam.13492] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 03/25/2021] [Accepted: 04/13/2021] [Indexed: 12/12/2022]
Abstract
Antimicrobial susceptibility testing with the last-resort antibiotics polymyxins (polymyxin B and colistin) is associated with several methodological issues. Currently, broth microdilution (BMD) is recommended for colistin and polymyxin B. BMD is laborious and the utility of alternative methods needs to be evaluated for polymyxin B susceptibility testing. In this study, using BMD as a reference method, the performance of agar dilution (AD) and MIC test strips (MTS) were evaluated in polymyxin B susceptibility testing. BMD, AD and MTS were used to determine MICs of 193 clinical isolates of Escherichia coli. Seventy-nine were positive for the polymyxin resistance gene mcr-1. Method performances were evaluated based on pair-wise agreements with the reference method (BMD) and statistical testing. AD and MTS showed an unacceptable number of very major errors (VMEs) compared with BMD, 9·3 and 10·7%, respectively. The essential agreement (EA) was low for AD (49·7%), but high for MTS (97·8%). However, statistical testing showed that MTS tended to yield a one-step lower MIC (P < 0·01) compared with BMD. The discordances observed with MTS and AD in comparison with BMD for polymyxin B susceptibility testing for E. coli suggest their inapplicability in routine testing. A large number of isolates clustered around the susceptibility breakpoint (2-4 mg l-1 ) and several mcr-1 positive isolates (17%) were determined as susceptible with BMD. A screening breakpoint for mcr-1 of 2 mg l-1 should also be considered.
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Affiliation(s)
- Y Wang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - B Berglund
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Institution of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Y Zhu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Q Luo
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Y Xiao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
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19
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Hayakawa Ito de Sousa AT, Dos Santos Costa MT, Makino H, Cândido SL, de Godoy Menezes I, Lincopan N, Nakazato L, Dutra V. Multidrug-resistant mcr-1 gene-positive Klebsiella pneumoniae ST307 causing urinary tract infection in a cat. Braz J Microbiol 2021; 52:1043-1046. [PMID: 33713022 PMCID: PMC8105429 DOI: 10.1007/s42770-021-00466-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 02/28/2021] [Indexed: 10/21/2022] Open
Abstract
RESUMO The Klebsiella pneumoniae (K. pneumoniae) bacterium is responsible for many opportunistic infections such as sepsis, and a multidrug-resistant (MDR) clone sequence type (ST) 307 has recently begun to spread. The objective of this study was to report the first occurrence of this virulent genotype, which was found in the context of a urinary infection in a domestic feline in Brazil. The K. pneumoniae isolate was identified from the urine of a 6-month-old male crossbreed cat using 16S rRNA sequencing. It was then subjected to antimicrobial susceptibility testing, followed by multilocus sequence typing analysis, and PCR detection of virulence and resistance genes. The antimicrobial susceptibility profile demonstrated that the isolate was MDR and associated with the presence of the colistin resistance gene (mcr-1). Genotyping allowed us to classify the isolate as K. pneumoniae ST307 with the presence of wabG, uge, and entB genes. MDR K. pneumoniae is important in human and veterinary medicine because it causes many types of infections. Clonal propagation of virulent or MDR genotypes such as K. pneumoniae ST307 is a global concern. This report of ST307 isolation from a urine sample in a domestic feline is the first in Brazil.
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Affiliation(s)
- Alessandra Tammy Hayakawa Ito de Sousa
- Laboratory of Microbiology, Veterinary Hospital, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil.
- School of Veterinary Medicine, Federal University of Mato Grosso, Cuiabá, Brazil.
| | | | - Herica Makino
- Laboratory of Microbiology, Veterinary Hospital, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil
| | - Stéfhano Luis Cândido
- Laboratory of Microbiology, Veterinary Hospital, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil
| | - Isabela de Godoy Menezes
- Mycology Laboratory, Faculty of Pharmaceutical Sciences (FCF), University of São Paulo, São Paulo, Brazil
| | - Nilton Lincopan
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Luciano Nakazato
- Laboratory of Microbiology, Veterinary Hospital, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil
| | - Valéria Dutra
- Laboratory of Microbiology, Veterinary Hospital, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil
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20
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Seo J, Wi YM, Kim JM, Kim YJ, Ko KS. Detection of colistin-resistant populations prior to antibiotic exposure in KPC-2-producing Klebsiella pneumoniae clinical isolates. J Microbiol 2021; 59:590-597. [PMID: 33779958 DOI: 10.1007/s12275-021-0610-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/26/2021] [Accepted: 02/09/2021] [Indexed: 12/12/2022]
Abstract
Although colistin is frequently regarded as the antibiotic of last resort in treating carbapenem-resistant Klebsiella pneumoniae, colistin heteroresistance may in part be associated with antibiotic treatment failure. However, we do not know how widespread the colistin heteroresistance is in carbapenem-resistant K. pneumoniae isolates. In this study, we performed colistin disc diffusion assays, E-tests, and population analysis profiling for KPC-2-producing K. pneumoniae isolates to identify colistin heteroresistance. Although no colistin-resistant colonies were detected by the disc diffusion test and E-test, a colistin-resistant subpopulation was identified in population analysis profiling in all colistin-susceptible, KPC-2-producing K. pneumoniae isolates. Colistin-resistant subpopulations were also identified even when isolates had no colistin exposure. The ratio of colistin-resistant subpopulations to the total population increased as the exposure concentration of colistin increased. In in vitro time-kill assays, regrowth was observed in all isolates after 2 h upon exposure to colistin. We identified common amino acid alterations in PhoQ, PhoP, and PmrB in colistin-resistant subpopulations from some isolates, but no substitutions were found in most resistant subpopulations from other isolates. In all colistin-resistant subpopulations, overexpression of PhoQ and PbgP was observed. In this study, we demonstrated that colistin heteroresistance may be common in KPC-2-producing K. pneumoniae isolates, which could not be detected in the disc diffusion method and E-test. Colistin heteroresistance may cause colistin treatment failure in part and may evolve into resistance. Thus, development of more reliable diagnostic methods is required to detect colistin heteroresistance.
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Affiliation(s)
- Jungyu Seo
- Department of Microbiology and Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea
| | - Yu Mi Wi
- Division of Infectious Diseases, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, 51353, Republic of Korea
| | - Jong Min Kim
- Department of Pediatrics, Myongji Hospital, Goyang, 10475, Republic of Korea
| | - Yae-Jean Kim
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, 06355, Republic of Korea
| | - Kwan Soo Ko
- Department of Microbiology and Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea.
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21
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Galani I, Karaiskos I, Giamarellou H. Multidrug-resistant Klebsiella pneumoniae: mechanisms of resistance including updated data for novel β-lactam-β-lactamase inhibitor combinations. Expert Rev Anti Infect Ther 2021; 19:1457-1468. [PMID: 33945387 DOI: 10.1080/14787210.2021.1924674] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Introduction: Multi-drug-resistant Klebsiella pneumoniae is currently one of the most pressing emerging issues in bacterial resistance. Treatment of K.pneumoniae infections is often problematic due to the lack of available therapeutic options, with a relevant impact in terms of morbidity, mortality and healthcare-associated costs. Soon after the launch of Ceftazidime-Avibactam, one of the approved new β-lactam/β-lactamase inhibitor combinations, reports of ceftazidime-avibactam-resistant strains developing resistance during treatment were published. Being a hospital-associated pathogen, K.pneumoniae is continuously exposed to multiple antibiotics resulting in constant selective pressure, which in turn leads to additional mutations that are positively selected.Areas covered: Herein the authors present the K.pneumoniae mechanisms of resistance to different antimicrobials, including updated data for ceftazidime-avibactam.Expert opinion: K.pneumoniae is a nosocomial pathogen commonly implicated in hospital outbreaks with a propensity for antimicrobial resistance toward mainstay β-lactam antibiotics and multiple other antibiotic classes. Following the development of drug resistance and understanding the mechanisms involved, we can improve the efficacy of current antimicrobials, by applying careful stewardship and rational use to preserve their potential utility. The knowledge on antibiotic resistance mechanisms should be used to inform the design of novel therapeutic agents that might not be subject to, or can circumvent, mechanisms of resistance.
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Affiliation(s)
- Irene Galani
- Medicine, Infectious Diseases Laboratory, 4thDepartment of Internal Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Ilias Karaiskos
- 1st Department of Internal Medicine-Infectious Diseases, Hygeia General Hospital, Athens, Greece
| | - Helen Giamarellou
- 1 Department of Internal Medicine-Infectious Diseases, Hygeia General Hospital, Athens, Greece
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22
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Abstract
Antibiotic resistance is a major global health challenge and, worryingly, several key Gram negative pathogens can become resistant to most currently available antibiotics. Polymyxins have been revived as a last-line therapeutic option for the treatment of infections caused by multidrug-resistant Gram negative bacteria, in particular Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacterales. Polymyxins were first discovered in the late 1940s but were abandoned soon after their approval in the late 1950s as a result of toxicities (e.g., nephrotoxicity) and the availability of "safer" antibiotics approved at that time. Therefore, knowledge on polymyxins had been scarce until recently, when enormous efforts have been made by several research teams around the world to elucidate the chemical, microbiological, pharmacokinetic/pharmacodynamic, and toxicological properties of polymyxins. One of the major achievements is the development of the first scientifically based dosage regimens for colistin that are crucial to ensure its safe and effective use in patients. Although the guideline has not been developed for polymyxin B, a large clinical trial is currently being conducted to optimize its clinical use. Importantly, several novel, safer polymyxin-like lipopeptides are developed to overcome the nephrotoxicity, poor efficacy against pulmonary infections, and narrow therapeutic windows of the currently used polymyxin B and colistin. This review discusses the latest achievements on polymyxins and highlights the major challenges ahead in optimizing their clinical use and discovering new-generation polymyxins. To save lives from the deadly infections caused by Gram negative "superbugs," every effort must be made to improve the clinical utility of the last-line polymyxins. SIGNIFICANCE STATEMENT: Antimicrobial resistance poses a significant threat to global health. The increasing prevalence of multidrug-resistant (MDR) bacterial infections has been highlighted by leading global health organizations and authorities. Polymyxins are a last-line defense against difficult-to-treat MDR Gram negative pathogens. Unfortunately, the pharmacological information on polymyxins was very limited until recently. This review provides a comprehensive overview on the major achievements and challenges in polymyxin pharmacology and clinical use and how the recent findings have been employed to improve clinical practice worldwide.
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Affiliation(s)
- Sue C Nang
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
| | - Mohammad A K Azad
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
| | - Tony Velkov
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
| | - Qi Tony Zhou
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
| | - Jian Li
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
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23
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Azam M, Gaind R, Yadav G, Sharma A, Upmanyu K, Jain M, Singh R. Colistin Resistance Among Multiple Sequence Types of Klebsiella pneumoniae Is Associated With Diverse Resistance Mechanisms: A Report From India. Front Microbiol 2021; 12:609840. [PMID: 33692764 PMCID: PMC7937630 DOI: 10.3389/fmicb.2021.609840] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 01/22/2021] [Indexed: 12/25/2022] Open
Abstract
Background: The resistance to colistin and carbapenems in Klebsiella pneumoniae infections have been associated with increased morbidity and mortality worldwide. A retrospective observational study was conducted to determine the prevalence and molecular events contributing to colistin resistance. Methods: Clinical samples were screened for colistin resistance and underlying mechanisms were studied by PCR-based amplification and sequence analysis of genes of two-component regulatory system (phoPQ and pmrAB), regulatory transmembrane protein-coding mgrB, and mobilized colistin resistance genes (mcr-1-8). Gene expression of pmrC and pmrK was analyzed by qRT-PCR, and the genetic relationship was assessed by MLST. The putative effect of amino-acid substitutions was predicted by a combination of bioinformatics tools. Results: Of 335 Klebsiella spp. screened, 11 (3.2%) were identified as colistin-resistant (MIC range, 8 to >128 μg/ml). K. pneumoniae isolates belonged to clonal complex-11 (CC11) with sequence types (STs): 14, 16, 43, 54, 147 and 395, whereby four isolates conferred three novel STs (3986, 3987 and 3988) profiles. Sequence analysis revealed non-synonymous potentially deleterious mutations in phoP (T151A), phoQ (del87–90, del263–264, L30Q, and A351D), pmrA (G53S), pmrB (D150V, T157P, L237R, G250C, A252G, R315P, and Q331H), and mgrB (C28G) genes. The mgrB gene in three strains was disrupted by insertion sequences encoding IS1-like and IS5/IS1182 family-like transposase genes. All 11 isolates showed an elevation in the transcription level of pmrC gene. Mobilized colistin-resistance (mcr) genes were not detected. All but one of the colistin-resistant isolates was also resistant to carbapenems; β-lactamase genes blaNDM-1-like, blaOXA-48-like, and blaCTX-M-like were detected in eight, five, and nine isolates, respectively. Conclusion: All the studied colistin- and carbapenem-resistant K. pneumoniae isolates were genetically distinct, and various mechanisms of colistin resistance were detected, indicating its spontaneous emergence in this bacterial species.
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Affiliation(s)
- Mudsser Azam
- ICMR-National Institute of Pathology, New Delhi, India
| | - Rajni Gaind
- Department of Microbiology, VMMC and Safdarjung Hospital, New Delhi, India
| | - Gulshan Yadav
- ICMR-National Institute of Pathology, New Delhi, India
| | - Amit Sharma
- Department of Microbiology, VMMC and Safdarjung Hospital, New Delhi, India
| | - Kirti Upmanyu
- ICMR-National Institute of Pathology, New Delhi, India
| | - Manisha Jain
- Department of Microbiology, VMMC and Safdarjung Hospital, New Delhi, India
| | - Ruchi Singh
- ICMR-National Institute of Pathology, New Delhi, India
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24
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Lopes SP, Jorge P, Sousa AM, Pereira MO. Discerning the role of polymicrobial biofilms in the ascent, prevalence, and extent of heteroresistance in clinical practice. Crit Rev Microbiol 2021; 47:162-191. [PMID: 33527850 DOI: 10.1080/1040841x.2020.1863329] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Antimicrobial therapy is facing a worrisome and underappreciated challenge, the phenomenon of heteroresistance (HR). HR has been gradually documented in clinically relevant pathogens (e.g. Pseudomonas aeruginosa, Staphylococcus aureus, Burkholderia spp., Acinetobacter baumannii, Klebsiella pneumoniae, Candida spp.) towards several drugs and is believed to complicate the clinical picture of chronic infections. This type of infections are typically mediated by polymicrobial biofilms, wherein microorganisms inherently display a wide range of physiological states, distinct metabolic pathways, diverging refractory levels of stress responses, and a complex network of chemical signals exchange. This review aims to provide an overview on the relevance, prevalence, and implications of HR in clinical settings. Firstly, related terminologies (e.g. resistance, tolerance, persistence), sometimes misunderstood and overlapped, were clarified. Factors generating misleading HR definitions were also uncovered. Secondly, the recent HR incidences reported in clinically relevant pathogens towards different antimicrobials were annotated. The potential mechanisms underlying such occurrences were further elucidated. Finally, the link between HR and biofilms was discussed. The focus was to recognize the presence of heterogeneous levels of resistance within most biofilms, as well as the relevance of polymicrobial biofilms in chronic infectious diseases and their role in resistance spreading. These topics were subject of a critical appraisal, gaining insights into the ascending clinical implications of HR in antimicrobial resistance spreading, which could ultimately help designing effective therapeutic options.
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Affiliation(s)
- Susana Patrícia Lopes
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Paula Jorge
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Ana Margarida Sousa
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Maria Olívia Pereira
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
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25
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Emergence of the Novel Aminoglycoside Acetyltransferase Variant aac(6')-Ib-D179Y and Acquisition of Colistin Heteroresistance in Carbapenem-Resistant Klebsiella pneumoniae Due to a Disrupting Mutation in the DNA Repair Enzyme MutS. mBio 2020; 11:mBio.01954-20. [PMID: 33443109 PMCID: PMC8534291 DOI: 10.1128/mbio.01954-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Amikacin and colistin are effective against carbapenem-resistant Klebsiella pneumoniae In 2017, we successively isolated three carbapenem-resistant K. pneumoniae isolates (ST967) from a patient with chronic renal failure in Japan. The first (SMKP01, sputum, day 0) and second (SMKP02, blood, day 14) strains were resistant to most antimicrobials tested but still susceptible to amikacin (MICs of 4 and 0.5 mg/liter, respectively) and colistin (MIC of 0.5 mg/liter for both). The third strain (SMKP03, blood, day 51) was not susceptible to amikacin (MIC, 32 mg/liter), and its MIC for colistin varied (0.5 to 8 mg/liter). Whole-genome sequencing of SMKP01 revealed that 17 of 20 antimicrobial resistance genes, including qnrB91 (a novel qnrB2 variant) and aac(6')-Ib-cr, were located on an 86.9-kb IncFII-IncQ plasmid. The qnrB91 conferred greater fluoroquinolone resistance than qnrB2 SMKP03 aac(6')-Ib-cr that possessed a gene mutation that resulted in an R102W substitution, namely, aac(6')-Ib-D179Y, made a greater contribution to amikacin resistance than did aac(6')-Ib-cr SMKP03 harbored a nonsense mutation in mutS, which encodes a DNA repair enzyme. Introduction of this mutation into SMKP01 (SMKP01mutS A307T) resulted in a dramatic increase (>58-fold) in the frequency of spontaneous amikacin-resistant mutants relative to SMKP01, and the substantial mutants possessed aac(6')-Ib-D179Y SMKP01mutS A307T exhibited an unstable MIC for colistin (0.5 to 8 mg/liter). The results demonstrate that a disruptive mutation in MutS, arising during the clinical course of an infection, created a platform for the acquisition of amikacin nonsusceptibility and colistin heteroresistance in multidrug-resistant K. pneumoniae, mediated by the elevated frequency of spontaneous mutations.IMPORTANCE The emergence of multidrug resistance in pathogens such as Klebsiella pneumoniae is of great clinical concern. Antimicrobial resistance sometimes arises during the course of an infection. Although many studies have reported the emergence of antimicrobial resistance and novel antimicrobial resistance genes in the clinical isolates, the identity of the bacterial factor(s) that generate this emergence is still unclear. We report that a disruptive mutation in MutS, arising during the clinical course of an infection, created a context for the acquisition of colistin resistance and the emergence of a novel variant of the amikacin resistance gene in multidrug-resistant K. pneumoniae via an increase in the frequency of spontaneous mutation. This observation is important for understanding how K. pneumoniae develops multidrug resistance during infection and could potentially lead to new antimicrobial treatments for high-risk pathological microbes.
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26
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Evolution of Colistin Resistance in the Klebsiella pneumoniae Complex Follows Multiple Evolutionary Trajectories with Variable Effects on Fitness and Virulence Characteristics. Antimicrob Agents Chemother 2020; 65:AAC.01958-20. [PMID: 33139278 DOI: 10.1128/aac.01958-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 10/25/2020] [Indexed: 12/14/2022] Open
Abstract
The increasing prevalence of multidrug-resistant Klebsiella pneumoniae has led to a resurgence in the use of colistin as a last-resort drug. Colistin is a cationic antibiotic that selectively acts on Gram-negative bacteria through electrostatic interactions with anionic phosphate groups of the lipid A moiety of lipopolysaccharides (LPSs). Colistin resistance in K. pneumoniae is mediated through loss of these phosphate groups, their modification by cationic groups, and by the hydroxylation of acyl groups of lipid A. Here, we study the in vitro evolutionary trajectories toward colistin resistance in four clinical K. pneumoniae complex strains and their impact on fitness and virulence characteristics. Through population sequencing during in vitro evolution, we found that colistin resistance develops through a combination of single nucleotide polymorphisms, insertions and deletions, and the integration of insertion sequence elements, affecting genes associated with LPS biosynthesis and modification and capsule structures. Colistin resistance decreased the maximum growth rate of one K. pneumoniae sensu stricto strain, but not those of the other three K. pneumoniae complex strains. Colistin-resistant strains had lipid A modified through hydroxylation, palmitoylation, and l-Ara4N addition. K. pneumoniae sensu stricto strains exhibited cross-resistance to LL-37, in contrast to the Klebsiella variicola subsp. variicola strain. Virulence, as determined in a Caenorhabditis elegans survival assay, was increased in two colistin-resistant strains. Our study suggests that nosocomial K. pneumoniae complex strains can rapidly develop colistin resistance through diverse evolutionary trajectories upon exposure to colistin. This effectively shortens the life span of this last-resort antibiotic for the treatment of infections with multidrug-resistant Klebsiella.
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27
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Abstract
Despite increasing evidence suggesting that antibiotic heteroresistance can lead to treatment failure, the significance of this phenomena in the clinic is not well understood, because many clinical antibiotic susceptibility testing approaches lack the resolution needed to reliably classify heteroresistant strains. Here we present G0790, a new globomycin analog and potent inhibitor of the Escherichia coli type II signal peptidase LspA. We demonstrate that in addition to previously known mechanisms of resistance to LspA inhibitors, unstable genomic amplifications containing lspA can lead to modest yet biologically significant increases in LspA protein levels that confer a heteroresistance phenotype. Clinical development of antibiotics with novel mechanisms of action to kill pathogenic bacteria is challenging, in part, due to the inevitable emergence of resistance. A phenomenon of potential clinical importance that is broadly overlooked in preclinical development is heteroresistance, an often-unstable phenotype in which subpopulations of bacterial cells show decreased antibiotic susceptibility relative to the dominant population. Here, we describe a new globomycin analog, G0790, with potent activity against the Escherichia coli type II signal peptidase LspA and uncover two novel resistance mechanisms to G0790 in the clinical uropathogenic E. coli strain CFT073. Building on the previous finding that complete deletion of Lpp, the major Gram-negative outer membrane lipoprotein, leads to globomycin resistance, we also find that an unexpectedly modest decrease in Lpp levels mediated by insertion-based disruption of regulatory elements is sufficient to confer G0790 resistance and increase sensitivity to serum killing. In addition, we describe a heteroresistance phenotype mediated by genomic amplifications of lspA that result in increased LspA levels sufficient to overcome inhibition by G0790 in culture. These genomic amplifications are highly unstable and are lost after as few as two subcultures in the absence of G0790, which places amplification-containing resistant strains at high risk of being misclassified as susceptible by routine antimicrobial susceptibility testing. In summary, our study uncovers two vastly different mechanisms of resistance to LspA inhibitors in E. coli and emphasizes the importance of considering the potential impact of unstable and heterogenous phenotypes when developing antibiotics for clinical use.
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28
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Colistin Heteroresistance among Extended Spectrum β-lactamases-Producing Klebsiella pneumoniae. Microorganisms 2020; 8:microorganisms8091279. [PMID: 32825799 PMCID: PMC7569871 DOI: 10.3390/microorganisms8091279] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/14/2020] [Accepted: 08/20/2020] [Indexed: 01/24/2023] Open
Abstract
Colistin-heteroresistant (CST-HR) Enterobacterales isolates have been identified recently, challenging the clinical laboratories since routine susceptibility tests fail to detect this phenotype. In this work we describe the first CST-HR phenotype in extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae isolates in South America. Additionally, we determine the genomic mechanisms of colistin heteroresistance in these strains. The CST-HR phenotype was analyzed by the population analysis profile (PAP) method, and mutations associated with this phenotype were determined by whole-genome sequencing (WGS) and the local BLAST+ DB tool. As a result, 8/60 isolates were classified as CST-HR according to the PAP method. From WGS, we determined that the CST-HR isolates belong to three different Sequence Types (STs) and four K-loci: ST11 (KL15 and KL81), ST25 (KL2), and ST1161 (KL19). We identified diverse mutations in the two-component regulatory systems PmrAB and PhoPQ, as well as a disruption of the mgrB global regulator mediated by IS1-like and IS-5-like elements, which could confer resistance to CST in CST-HR and ESBL-producing isolates. These are the first descriptions in Chile of CST-HR in ESBL-producing K. pneumoniae isolates. The emergence of these isolates could have a major impact on the effectiveness of colistin as a “last resort” against these isolates, thus jeopardizing current antibiotic alternatives; therefore, it is important to consider the epidemiology of the CST-HR phenotype.
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29
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Conceição-Neto OC, da Costa BS, Pontes LS, Santos ICO, Silveira MC, Cordeiro-Moura JR, Pereira NF, Tavares-Teixeira CB, Picão RC, Rocha-de-Souza CM, Carvalho-Assef APD. Difficulty in detecting low levels of polymyxin resistance in clinical Klebsiella pneumoniae isolates: evaluation of Rapid Polymyxin NP test, Colispot Test and SuperPolymyxin medium. New Microbes New Infect 2020; 36:100722. [PMID: 32642069 PMCID: PMC7334411 DOI: 10.1016/j.nmni.2020.100722] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 06/06/2020] [Accepted: 06/22/2020] [Indexed: 01/29/2023] Open
Abstract
Polymyxins are important therapeutic options for treating infections, mainly those caused by carbapenem-resistant Klebsiella pneumoniae. Specific chemical characteristics of polymyxins make it difficult to perform antimicrobial susceptibility testing, especially within the clinical laboratory. Here we aimed to evaluate the performance of three phenotypic methods: Rapid NP Polymyxin Test, ColiSpot test and the SuperPolymyxin medium. To accomplish this, 170 non-duplicate clinical K. pneumoniae isolates were analysed (123 colistin-resistant and 47 susceptible). The sensitivity and specificity obtained for Rapid Polymyxin NP Test, Colispot and SuperPolymyxin medium were, respectively, 90% and 94%, 74% and 100%, and 82% and 85%. Very major errors occurred more frequently in low-level colistin-resistant isolates (MICs 4 and 8 μg/mL). Rapid Polymyxin NP proved to be a method capable of identifying colistin-resistant strains in acceptable categorical agreement. However, major errors and very major errors of this method were considered unacceptable for colistin-resistance screening. Although the Colispot test is promising and easy to perform and interpret, the results did not reproduce well in the isolates tested. The colistin-containing selective medium (SuperPolymyxin) showed limitations, including quantification of mucoid colonies and poor stability. Nevertheless, Colispot and SuperPolymyxin medium methods did not present acceptable sensitivity, specificity and categorical agreement. It is essential to use analytical tools that faithfully reproduce bacterial resistance in vitro, especially in last-line drugs, such as polymyxins, when misinterpretation of a test can result in therapeutic ineffectiveness.
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Affiliation(s)
- O C Conceição-Neto
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
| | - B S da Costa
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
| | - L S Pontes
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
| | - I C O Santos
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
| | - M C Silveira
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
| | - J R Cordeiro-Moura
- Laboratório de Investigação em Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - N F Pereira
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
| | - C B Tavares-Teixeira
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
| | - R C Picão
- Laboratório de Investigação em Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - C M Rocha-de-Souza
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
| | - A P D Carvalho-Assef
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
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